Attrition mill



March 1, 1932. w. KEEFER 1,847,967

ATTRITION MILL Filed Oct. 6, 1928 fnvenf5r+ AZ ZcZYfZZZrnq' vPatented Mar. 1, 1932 UNITED STATES PATENT OFFICE WALTER L. KEEPER, OF CHAMBERSIBURG, PENNSYLVANIA, ASSIGNOR TO THE WOLF COMPANY, OF CHAMBERSBUBG, PENNSYLVANIA, A CORPORATION OF PENNSYL- VAN IA ATTRITION MILL Application filed October 6, 1928. Serial-No. 310,825.

This invention relates to attrition mills and is more particularly concerned with an attrition mill having a centrifugal feeder.

An object of the invention is to produce a new and improved form of attrition mill.

Another object is to produce an attrition mill having a centrifugal feeder.

Another object is to produce an attrition mill with plates having a large eye.

Another object is to produce an attrition mill having a centrifugal feeder, the material to be crushed being fed from the feeder to the grinding plates through a large eye.

Yet another object is to produce an attrition mill having stationary and rotary crushing elements between which is mounted a centrifugal feeder.

' Other objects will appear hereinafter.

In the drawings, representing one modification of my invention,

Fig. 1 is a view partly in side elevation and partly in section of the assembled device; while Fig. 2 is an elevation showing the details of one of the grinding plates.

At 1 is shown the base on which is mounted a motor 2 and bearings 3 and 4 for a shaft 5. At one end of the shaft 5 there may be mounted any suitable form of micrometer adjusting means 6 for a purpose which will be developed later. At the other end of the shaft, is a suitable housing 7 for the runner 8. A housin -cover 9 closes the front of the housing 7. arried by the housing-cover is a stationary grinding plate 10 secured thereto by any desired means, such as bolts or the like. A similar grinding plate 11 is carried by the runner 8 and is likewise secured thereto by bolts or other suitable means.

The housing-cover 9 comprises a spout 12 which terminates at its lower end in a grain inlet 13. Through this inlet grain or other material to be crushed is fed into the centrifugal feeder 14 mounted on shaft 5 and which rotates in a path defined by the inner wall of the cover 9, and by the runner 8. A belt 15 transmits the power from shaft 5 to a pulley 16 attached to a countershaft 17. Power from the countershaft is transferred to a hopper which determines the quantity of material fed to the spout 12. The material then falls through the spout from whence it p is fed through the inlet 13 into feeder 14.

A centrifugal feeder 14 creates a centrifugal force on the material which forces it into the plates 10 and 11 uniformly around the entire inside periphery of the plate opening or eye 19. The material cannot be repelled or forced back when it comes in contact with the plates. Since the feeder is enclosed by side walls, the material must be forced out radially into the plates. It is due to this particular construction and to the feature of the plates having a larger opening or eye defined by the inner perimeter of the grinding plates 10 and 11, that a much higher efliciency has been obtained.

This feeder picks up the material by means of its arms 18 and hurls it into the inclined annular passageway 19 between the grinding plates 10 and 11. From the passageway 19, the grain is forced under action of the rotating runner 8 into cells 20, formed by radial andcircumferential ridges 21 and 22 respectively, formed on the working face of the grinding plates 10 and 11. The grain or other small material is thoroughly pulverized as a result of being forced between the plates 10 and 11. The dischargedpulverized material is collected in any desired manner.

It is to be understood that the degree of fineness of the ground material may be accurately determined by the adjustment of the micrometer adjusting means 6.

Because of the feeder and grinding plates being in line with each other, no deflection of or obstruction to the path'of the centrifugally-tossed material occurs, as does in the device of the prior art. Accordingly, the fullest extent of centrifugal pressure is exerted on the material, inasmuch as it cannot esthe introduction of materialtherethrough, an opposed rotating grinding plate, said grinding plates having grinding surfaces concentric with said opening and having a mean diameter considerably greater than the diameter of the'opening, the face of the statihnary plate inwardly of its grinding face being smooth, the face of the rotating plate having substantially radial vanes for centrifugally feeding material to said grinding faces, the inner portion of the smooth inner face of the stationary grinding late partially overlapping the outer ends 0 the radial vanes.

WALTER L. KEEFER. 

